1. Field of the Invention
The present invention relates to a semiconductor device, a method for inspecting an appearance thereof, and an apparatus for inspecting an appearance thereof.
2. Description of Related Art
In general, semiconductor devices are each produced by laminating wiring layers, which each have a wiring pattern composed of plural wirings, and insulating layers on a semiconductor substrate. After the formation of each of the wiring layers, an appearance inspection of the wiring layer is usually made in order to inspect whether or not there is a defect, such as chipping-off of the wiring pattern or incorporation of an alien substance. This appearance inspection is performed, for example, by radiating light onto the surface of the wiring layer, receiving the light reflected on the wiring layer surface by means of an image pickup element, and then analyzing data obtained from the received light (see, for example, JP-A-2004-294194).
However, according to this method, the image pickup element may receive not only the reflected light from the wiring layer to be inspected but also reflected light from a underlying wiring layer disposed under the wiring layer to be inspected. In this case, the image pickup element detects a defect present in the underlying wiring layer, so that the precision of the appearance inspection lowers.